Recent advances in agricultural technology have allowed the harvesting and packing of produce directly in the field. After injecting a water and ice solution, commonly referred to as liquid ice, into the cartons the produce is ready for shipment to the market. By use of a portable icing station close to the harvest field, two main benefits are derived. Firstly, the icing equipment can be amortized over a longer period throughout the year because the equipment can be used with more types of produce at different locations, and secondly, travel time and costs of transportation for the produce are reduced significantly by doing away with the time previously necessary to transport the produce to a fixed location ice plant.
In the past, portable ice generating equipment has been limited in generating capacity. Usually, such ice generating equipment utilizes a plate ice generator in which a liquid coolant is circulated through the center of a plurality of plate assemblies and water is passed over the exterior and allowed to freeze into ice sheets. Thereafter, by purging the plates of coolant and passing hot gas therethrough, the ice sheets are caused to disengage and drop downward for transport to a storage bin. Such generators have been limited in overall capacity due to the limited number of plates that have been mounted in the freezing section of a portable generator. Additionally, it has been usual to freeze on only one side of the plates. Further problems have existed with the ice encircling the plate ends and locking the ice sheet to the plates or, due to surface design, ice latching to the plate surface thereby making it difficult to disengage.
Attempts to solve the locking problem have involved either the limiting of the water flow to the center section of the plates to prevent the flow of water adjacent the edges of the plates, or the circulation of a hot fluid through passages in the edges of the plates to prevent the formation of ice in that area. Naturally, both of these designs have limited the overall capacity of the freezing unit. Additionally, if the ice is formed, separated from the plates, and then exposed to water, it can refreeze into a solid mass if the temperature of the ice is low enough. To prevent this occurrence, it has been common to limit the overall quantity of water passed over each plate in an effort to limit the amount of water dropping from the plates onto the separated ice.
It is the purpose of the present invention to provide a portable ice generator having a significantly greater ice making capacity than previous portable machines. Further, the invention allows for positive disengagement of the ice sheets from the plates and limits refreezing of the ice for easier handling once it is separated from the plates.